I get where you’re coming from, but I actually had the opposite happen. When I started sealing up my old place, I worried about trapping moisture inside too, but it turned out I was actually letting in more outside air than I realized. I went step-by-step: first sealed the basement, then checked the attic and around the windows. What made the biggest difference for me was adding a bathroom vent fan (which the house never had), and running it after showers. That seemed to cut down on a ton of the window condensation, even in winter.
I do think sealing is important, but it’s easy to miss the ventilation side of things. Sometimes just adding a vent or making sure your dryer isn’t leaking humid air inside does more than another round of caulk. It’s all about finding the right balance—too tight and you get moisture issues, too loose and you’re heating the outdoors. Every house is a bit different, especially these older ones with their quirks...
It’s all about finding the right balance—too tight and you get moisture issues, too loose and you’re heating the outdoors.
That’s exactly what tripped me up in my 1950s ranch. I sealed everything up tight one fall, only to have water running down the windows by Thanksgiving. Ended up cracking a window most days just to keep things sane. Funny how these old houses keep you guessing...
That’s a classic problem with older homes—air sealing is great until you realize you’ve basically created a terrarium indoors. I see it all the time: people go to town with caulk and weatherstripping, but forget old houses need to breathe a bit. Once you cut off that natural ventilation, all the moisture from showers, cooking, even just breathing, has nowhere to go. Next thing you know, condensation city.
Honestly, cracking a window isn’t the worst stopgap. But if you want a more permanent fix, sometimes adding a simple bath fan or even a trickle vent can make a world of difference. I’ve had clients swear by those little humidity sensors too—they’re not perfect, but at least you know when things are getting out of hand.
Funny how these houses keep teaching us lessons decades later... It’s always a balancing act between comfort and keeping the place from turning into a greenhouse.
I've seen this play out more times than I can count. Folks get all excited sealing every gap, and then a winter or two later, they're calling me about moldy window sills or weird damp spots. I get it—nobody wants drafts, but these old places were practically designed to leak air. Seal them up too tight and you’re just trapping all that moisture.
One job sticks out: a 1920s bungalow where the owners went nuts with spray foam and weatherstripping. Their energy bills dropped, sure, but suddenly their windows were fogging up like crazy, even in the bedrooms. Ended up cutting in a couple of bathroom fans and a kitchen vent, plus I convinced them to try a trickle vent above the living room window. Took a while, but things balanced out—no more condensation, and the house didn’t feel stuffy anymore.
Honestly, I’m not convinced you can ever get it *perfect* with these older homes. It’s always a bit of trial and error. Sometimes the low-tech fixes—like just cracking a window when you shower—work better than anything fancy.
- That sounds a lot like what I’m dealing with. I thought sealing up every crack would be a win, but now I’m second-guessing it.
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“Seal them up too tight and you’re just trapping all that moisture.”
This hit home. I noticed after I did a bunch of caulking and new weatherstripping, the bathroom mirror started fogging way more, and I even got some weird dampness near the baseboards. Never had that before.
- The whole “trial and error” thing makes sense. It’s kind of reassuring to know it’s not just me fumbling through this.
- I still can’t believe how much difference just running the bathroom fan makes. Didn’t think something so basic would help.
- Not sure I’ll ever get it perfect either, but at least now I know not to panic if things get a little weird after sealing stuff up. Guess these old houses really do need to breathe a bit.
- Appreciate your story—makes me feel less clueless about my own place.
The moisture thing is such a common side effect after tightening up a house. I’ve seen folks go all-in with caulk and foam, only to find condensation and even mold in places they never had it before. Out of curiosity, did you ever look into adding a fresh air intake or an HRV/ERV system? Sometimes just running a bath fan isn’t enough, especially in these older homes where airflow used to happen whether you wanted it or not. I always wonder where the right balance is—seal enough for efficiency, but not so much you’re fighting damp all winter.
I always wonder where the right balance is—seal enough for efficiency, but not so much you’re fighting damp all winter.
That’s the tricky part, isn’t it? I went a bit overboard with sealing up our 1950s ranch last fall—caulked every drafty window, foam around outlets, the whole deal. Our heating bill dropped, which was great, but then I started noticing the bathroom mirror fogging up way more, and the basement felt... mustier? Never had that before.
I haven’t added an HRV or ERV yet, mostly because of the cost and not really knowing if I’d be able to install it myself. I did try cracking a window on dry days and running the bath fan longer, but honestly, it feels like a band-aid. Sometimes I wonder if I should’ve left a few leaks alone just for the sake of airflow. Has anyone actually found a good middle ground? It’s weird how fixing one problem just creates another.
Sometimes I wonder if I should’ve left a few leaks alone just for the sake of airflow.
Same thing happened here after I sealed up my 60s split-level. Bills went down, but suddenly there’s condensation on windows and a weird damp smell in the laundry room. Never thought I’d miss those old drafts, honestly. Is it really worth it if you just trade one issue for another?
Yeah, I hear you. I went nuts with the caulk and weatherstripping a couple winters back—felt like I was living in a Ziploc bag after that. The drafts were gone, but my windows started fogging up and the basement got this musty vibe. Turns out, those little leaks actually helped air things out a bit.
I guess it’s one of those “pick your poison” deals. Lower bills are nice, but now I’m running the bathroom fan more and cracking a window here and there just to keep the place from feeling like a rainforest. Didn’t expect to be missing that chilly breeze under the front door, but at least my socks stay dry now.
If I had to do it over, I’d probably leave a couple of those old gaps alone or look into an actual ventilation system. Sometimes old houses just want to breathe, whether we like it or not.
That’s exactly what I’m worried about with my place. I’ve been tempted to seal up every draft, but then I hear stories like this and start second-guessing. My dad always said old houses “leak on purpose”—not sure that’s totally true, but I get it now. I’d rather deal with a chilly floor than that gross musty smell. Plus, running fans and cracking windows kind of defeats the whole point of weatherproofing, doesn’t it? Maybe there’s a sweet spot between “arctic wind tunnel” and “hermetically sealed tomb,” but I haven’t found it yet.